1. Field
This invention relates to air bag inflation systems including sensors and systems for profiling a mass positioned on a substrate and more specifically systems and structures for profiling the mass of that which is positioned on the seat of a vehicle such as an automobile.
2. State of the Art
Today many automobiles have an air bag system which activates to inflate an air bag and in turn position the air bag in front of the operator and in some cases to position another bag in front of the front seat passengers. Air bags have also been installed in side door panels of some vehicles. The purpose of the air bags is to act as a cushion and in turn reduce injury to the operator and passengers from interaction with front structures such as the steering wheel, dash board and windshield or with side structures such as the side door or side window of an automobile arising from a sudden impact and in turn sudden change of speed of the vehicle. For example, detectors are positioned to sense the sudden deceleration of the vehicle that may be imposed by an accident or crash. The detectors are connected to the air bag system to electrically activate gas generators positioned to inject gas into and inflate one or more large air bags. The air bags thereupon rapidly inflate or deploy to function, for example, one to cushion a driver and one to cushion the passenger, positioned on the front passenger seat of the automobile. That is, the air bags inhibit the forward movement of the driver and passenger due to inertia to eliminate the resulting injury should they move into contact with the vehicle. Air bags are also configured to deflate fairly quickly so that they will not interfere with, for example, breathing of the person or vehicle egress.
It seems to be accepted that air bag arrangements are responsible for protecting and saving many people who have been in serious accidents. However, air bags have been known to inflate when the vehicle and its occupants are not in any serious jeopardy. For example, vehicles encountering a large bump or hole in the road surface reportedly have had their air bag systems activate and inflate the air bags. Minor vehicle interactions (e.g., slow speed accidents) are also believed to have led to activation when the vehicle occupants are not in serious jeopardy. Activation in such cases can impose a rearward force on an occupant that is not desired. Also activation may interfere with the driver""s vision and in turn interfere with the operation of the vehicle.
The air bag for the driver is typically positioned in the hub of the steering wheel. In some vehicles, the horn has been moved from a typical or traditional central position to buttons on, for example, spokes of the steering wheel to provide the space for the air bag. Systems for operating the horn of the vehicle in a central position of the steering wheel have been devised even though the bag is in the hub. U.S. Pat. No. 5,576,684 (Langford), the disclosure of which is hereby incorporated by this reference, discloses a system suitable for use in the hub of the steering wheel with provisions for horn operation. Activation of the driver air bag inhibits driver interaction with the steering wheel, steering wheel column and even the windshield.
An inflating air bag proceeds outwardly from the vehicle structure and toward the occupant very rapidly so that it fills in the space in front of the occupant before the inertia forces on the occupant can cause the occupant to project into the vehicle structure. Thus an inflating air bag proceeds outwardly not only rapidly but also with some force inasmuch as it must absorb the force imposed on it by the forward moving occupant.
Inasmuch as the operator of a vehicle is typically over the age of 16, the range of design parameters for the driver air bag is within certain practical limits. Thus, should an air bag inflate, the speed and force exerted can be selected to be consistent with the physical characteristics (e.g., size, height, weight) of the operator. However, for the passenger seat in the front seat area of the vehicle, the occupant can range in size and configuration from a baby in a car seat to a small child to a full sized adult. Further, the front seat may have a wide variety of objects positioned on it ranging, by way of example, from a woman""s purse to a sack of groceries. Typical air bag systems do not sense the identity of the occupant or object in the seat. The air bag deploys even if there is no one or nothing in the passenger seat. Further, presently known air bag systems do not take into account the size or character of that which is in the passenger seat and are thereby unable to adjust to accommodate to the size and character of that which is in the front seat.
Because an air bag inflates with great speed and with a force sufficient to sustain the force of a large adult projecting forward at great speed, some adults are reportedly bruised or otherwise injured by the inflating air bag. Some small passengers are not able to sustain the force of the air bag and reportedly may sustain some significant injury thereby. There have been reports in the press of injuries and even fatalities of small children attributed to air bag inflation. See, P. Carbonara, IS THAT A BOMB IN YOUR DASHBOARD (MONEY magazine, NOVEMBER 1998, pp. 131-138).
To reduce injuries to small occupants, some effort is being made to install a switch to regulate the passenger side air bag. That is, an on-off switch is being incorporated into the air bag system so that an operator may deactivate the air bag depending on the nature/character of the passenger (e.g., a baby in a car seat carrier). Of course use of the on-off switch is believed to also propose risks if the operator places the switch in an xe2x80x9coffxe2x80x9d condition and fails to return it to xe2x80x9conxe2x80x9d for an appropriately sized passenger. It is also understood that some have proposed systems to vary the pressure of the air bag relative to the size of the occupant. However, no effective system for doing so is known at this time.
Systems to detect the presence of a seat occupant or object in the seat and also to determine certain characteristics sufficient to properly determine when air bag inflation is desired and when it is not desired and to provide a signal that may be used for a system to vary the pressure in the air bag have been proposed. However, such a system to be useful must be operative over a wide range of temperatures and be operative when immersed or wet. In such conditions, as well as, in normal dry conditions and temperature (e.g., 60xc2x0 F.), such systems must be able to supply signals that are suitable for determining or profiling a mass that ranges from very small to very large. Further such a system must be rugged and reliable. Such a system is not presently available or known.
An air bag system includes a detector arrangement with related circuits and components. The detector senses the presence of and supplies signals from which one may classify a mass (e.g., an object or person) positioned on a substrate such as the seat of a vehicle (e.g., automobile, truck, airplane). A sensor arrangement is positioned in the seat and configured to sense the mass and general configuration of that which is in the seat by sensing downward forces exerted in selected sectors of the seat. The sensor generates signals that are reflective of the mass on the seat. The signals are of the type which may thereafter be processed and compared with known information for a given mass to produce an output signal which arms or disarms the gas generator of an air bag to regulate the gas generator as desired.
In one form, the invention is a detector for positioning between a base and a surface. The detector is operable for detecting a force or pressure at one or more locations of a plurality of locations on a deformable surface and for generating a signal reflective of the presence of the force or pressure applied at the plurality of locations. In another form, the detector generates signals reflective of the profile and relative magnitude of the deflection and in turn the force or pressure.
A sensor mat is positioned between the base and the surface. The sensor mat is configured to mechanically deflect upon mechanical deflection of the surface toward the base upon application of the force or pressure to the surface at any one or more of the plurality of locations. The sensor mat has at least a plurality of sensors positioned for mechanical displacement upon the displacement of the surface. The sensor of said plurality of sensors is of the type which predictably changes a measurable electrical characteristic upon the application of a force thereto. Conductor means is connected to each sensor to supply electrical power thereto and is connected to at least one sensor of the plurality of sensors to transmit therefrom signals reflective of changes in the measurable electrical characteristic of the one sensor. A terminal means is conductively connected to the conductor means for electrical connection to a source of electrical power for receiving and supplying electrical power to said sensor mat and for electrical connection to an external circuit configured to receive signals reflective of said changes in the measurable electrical characteristic of at least the one sensor.
Preferably, the surface is divided into a plurality of sectors with each sector having one location of the plurality of locations. More preferably, a sensor of the plurality of sensors of the sensor mat is positioned proximate a location in a sector of the surface to mechanically deflect upon deflection of the sector at the location in that sector for supplying the signals reflecting a change in the electrical characteristic. Even more preferably, the plurality of sensors includes a separate selected plurality of sensors each of which has a predictable change in electrical resistance upon mechanical deflection thereof. One sensor or a plurality of the sensors may be force sensitive resistors.
In a preferred configuration, the conductor means includes a trunk member with a plurality of branch members extending therefrom. Each branch member has at least one sensor of the plurality of sensors, which is conductively connected thereto. More desirably, at least one branch member of the plurality of branch members has two sensors of the plurality of sensors connected thereto. In one configuration the mat includes six branch members. Preferably each of the six branch members includes two central members each having five sensors. Two outer members of the six branches each have three sensors. Inboard branch members include a left inboard member and a right inboard member each having six sensors of the plurality of sensors. Even more preferably, the sensor array is generally polygonal in projection. Each sensor is connected by conductors to a terminal circuit through a preferred connector.
In a desirable alternate, a deflector structure is positioned relative to a sensor for contacting the sensor upon application of the force in a sector of the surface.
At least one sensor of the selected plurality of sensors preferably has a substrate configured to deflect about a transverse axis and an electrically conductive composition deposited on a substrate to be deflected with the substrate about the transverse axis. The deflector structure is preferably constructed with a longitudinal axis which may be generally positioned to be in alignment with the transverse axis. Desirably the deflector structure is shaped to act as a fulcrum about which the substrate deflects upon application of said force at the location in a sector. The deflector structure is desirably sized to extend substantially the width of the substrate. In a highly preferred configuration the deflector structure is cylindrical in shape.
In one application or embodiment, the surface includes the outer material layer of a seat structure suitable for use in a vehicle. The base includes the structure of the seat structure covered with the outer material layer.
In one preferred embodiment, an air bag system is provided in which an air bag is configured to be inflated with a gas. The air bag includes a bag mechanism with a bag operable from a stored position to an expanded position by inflation with said gas. The air bag also includes gas supply means positioned for supplying gas to the air bag to urge the bag to its expanded position upon receipt of an activation signal.
The air bag system includes a sensor system for generating the activation signal. The sensor system includes a base positioned proximate the substrate with a sensor mat positioned between the base and the substrate so that upon mechanical deflection of the substrate toward the base at one or more of a plurality of locations, one or more of a plurality of sensors will deflect. Each sensor is positioned for mechanical deflection upon the deflection of the substrate at the plurality of locations. Each sensor of the plurality of sensors is of the type that predictably changes a measurable electrical characteristic upon mechanical deflection thereof.
The sensor system of the air bag also includes conductor means connected to each sensor to supply electrical power thereto and to transmit therefrom trigger signals reflective of changes in the measurable electrical characteristic of each sensor upon the application of a force or pressure to the surface. The sensor system also includes terminal means electrically associated with said conductor means for electrical connection to a source of electrical power for receiving and supplying electrical power to the sensors and to the conductor means for receiving and transmitting the trigger signals.
The sensor system of the desired air bag includes operation means conductively connected to a source of electrical power to receive electrical power therefrom and to the terminal means to receive trigger signals reflective of the changes in the measurable electrical characteristic of each sensor. The operation means is configured to compare the trigger signals with preselected operational values and calculate the difference or an error signals reflective of the magnitude of the differences there between, and to generate activation signals based on the presence of the difference or error signals of preselected magnitude. The operation means is conductively connected to the air bag means to supply said activation signals to said gas supply means.
Desirably the air bag is installed in and a part of a vehicle such as an automobile, bus, train, plane, or the like.
To profile the mass or at least one characteristic of that which is on the seat, a sensor array of the type hereinbefore is installed in the vehicle. The system includes a computer connected to the terminal structure programmed to process the signals and to enable the gas generator upon determination of a preselected mass and/or profile.